Semiconductor memory is widely used in various electronic devices such as cellular telephones, digital cameras, personal digital assistants, medical electronics, mobile computing devices, and non-mobile computing devices. Semiconductor memory may comprise non-volatile memory or volatile memory. A non-volatile memory allows information to be stored and retained even when the non-volatile memory is not connected to a source of power (e.g., a battery). Examples of non-volatile memory include flash memory (e.g., NAND-type and NOR-type flash memory) and Electrically Erasable Programmable Read-Only Memory (EEPROM).
A charge-trapping material can be used in non-volatile memory devices to store a charge which represents a data state. The charge-trapping material can be arranged vertically in a three-dimensional (3D) stacked memory structure. One example of a 3D memory structure is the Bit Cost Scalable (BiCS) architecture which comprises a stack of alternating conductive and dielectric layers. A memory hole is formed in the stack and a vertical NAND string is then formed by filling the memory hole with materials including a charge-trapping layer to create a vertical column of memory cells. Each memory cell can store one or more bits of data.
When a memory system is deployed in an electronic device, the non-volatile memory system may program data, read data and/or erase data. Errors may occur in data when the data is programmed, or after programming while the data is stored in the non-volatile memory. To allow such errors to be corrected, some redundant data may be calculated and stored with user data according to an encoding scheme. Encoding data prior to storage and decoding data read from a non-volatile memory may be performed by an Error Correction Code (ECC) encoder/decoder in a non-volatile memory system.